The use of remote controllers facilitates manipulation of household electrical appliances such as TV sets, video tape recorders, audio equipments, air conditioners, and so on. Recently, a lamp remote controller is used to handle on/off statuses, lighting styles, brightness, and light colors of the lamps. The user can handle the lamp within a distance of several meters from the lamp through the remote controller. Although the use of remote controller to control the lamp is convenient, there are still some drawbacks. For example, the remote controller should be stored in an easily accessible place; otherwise, it becomes quite inconvenient to search the remote controller. In addition, since various kinds of electrical appliances have their own remote controllers, the user is often confused with a lot of remote controllers and the selection of the actual remote controller becomes troublesome. Moreover, too many remote controllers are neither cost-effective nor user-friendly.
For reducing the dependence on remote controllers, a method for controlling a lamp according to the detected movement of a user's hand has been developed in WO 2006/056814, which is entitled “PROXIMITY SENSOR DIMMING CONTROL FOR A LIGHT”, and the contents of which are hereby incorporated by reference. The lamp disclosed in WO 2006/056814 includes an infrared emitter for providing an infrared beam and an infrared detector for detecting the reflected infrared beam which is reflected by an object (e.g. the user's hand) positioned in the path of the infrared beam. In a case that the user's hand enters the path of the infrared beam, the lamp is turned on. On the contrary, the lamp is turned off if the user's hand exits the path of the infrared beam. Generally, the intensity of infrared light reflected from the object and received by the infrared detector is dependent on the inverse square of the distance between the infrared detector and the object. By determining the movement of the user's hand away from or toward the infrared detector, the brightness of the light is decreased or increased. Since the intensity of infrared light detected by the infrared detector is interfered with the background brightness, the detecting accuracy is deteriorated. In addition, the operating range of the infrared detector is highly dependent on the intensity of the received infrared light.
Therefore, there is a need of providing a lighting device capable of controlling the light and minimally interfered with the ambient parameters.